Budding interests: Citizen scientists are tracking changes in flowering patterns

“I’ve been searching for the white neem blossoms. Grinding the flowers with a few tender neem leaves to make a chutney is an annual ritual during Gudi Padwa (the Maharashtrian new year celebrated in late March or early April). But there is no trace of either on the trees this year,” says Mumbai botanist Sayee Girdhari, 28.

Girdhari is a project coordinator with SeasonWatch, a citizen-science initiative that invites people to record the arrival of flowers, fruits and leaves in the trees around them. In the 10 years since the initiative started collecting this data, anecdotal evidence has pointed to shifts in traditionally established patterns, she says.

In Kerala, fewer mango trees appear to be blossoming at their peak in April-May. Anecdotal reports suggest that the blooming of the palash (Flame of the Forest), once used to make gulaal during Holi in North India, is changing too, according to ecologist Geetha Ramaswami, 38, a programme manager with SeasonWatch. Mahua trees in Madhya Pradesh, meanwhile, are yielding fewer flowers, while neem trees are blooming earlier than usual — before the March-end Ugadi festival — in Karnataka.

In order to gather more data, and help more citizens understand the links between seasonal patterns and foliage, SeasonWatch began hosting tree festivals in 2018. An ongoing edition of this quarterly festival ends today.

In each 10- to- 15-day event, citizens across the country are invited to record observations about trees in their neighbourhood. This includes data on which species are blossoming, which are sprouting new leaves; which house visible life such as birds’ nests or caterpillars.

The data is recorded on the SeasonWatch website and app, and collated and examined in partnership with the independent research organisation Nature Conservation Foundation (NCF); the National Centre for Biological Sciences (NCBS), which is part of the Tata Institute of Fundamental Research; and with support from the Wipro Foundation.

The portal has so far recorded over 6.11 lakh observations across more than 130 tree species, with most of those observations coming in during the quarterly tree festivals. “We get a lot more data in each 10-day festival than we get through the rest of the year combined,” Girdhari says. “The database can help with scientific studies. But the ultimate goal is to bring about policy-level changes in the way forests, and the factors that affect them, are managed.”

Why might the patterns be changing? Climate is one factor. Changes in groundwater levels, air pollution, water pollution, concretisation and changing land use patterns can have an impact too. And the availability of herbivores, leaf-eating insects and pollinators, and soil-water-nutrient levels can have an effect.

Studies elsewhere in the world have shown how changes in these patterns can affect dependent animal life, and eventually the food chain. In Wytham Woods in England, for instance, researchers at Oxford University tracked the habits of great tits for 60 years and found that new leaves in oak trees were appearing earlier in spring; the caterpillars that fed on them were appearing earlier too. As a result, the great tits, whose nestlings feed on these worms, had shifted their nesting time by nearly three weeks.

The impact can also be economic. An unseasonal heat wave in late February and early March has affected Alphonso mango blooms in Maharashtra. Farmers stand to lose almost three-fourths of the April-May harvest. In parts of Madhya Pradesh (MP) and Chhattisgarh, smaller mahua flower harvests could affect the liquor, sweets and condiments industries that depend on it as an ingredient.

In these regions, SeasonWatch has been working with local non-governmental organisations operating in the conservation and agriculture space to collate and verify submissions. In MP, for instance, the non-profit Foundation for Ecological Security (FES) has verified that fewer flowers are blooming.

It will take decades to determine exactly why, says Subimal Ghosh, convener of the interdisciplinary programme in climate studies at the Indian Institute of Technology-Bombay (IIT-B). “But the ways in which erratic climate could impact foliage are direct. Untimely high temperatures raise the vapour pressure deficit. This makes the air dry, which leaches humidity from foliage and can cause water stress in trees. Unseasonal very heavy rains can result in a dilution of nutrients.”

Involving citizens is pivotal, Ghosh adds. They have a vital role to play in collecting data. “Instead of scientists and the government working in silos, we need to build more participatory frameworks to include people,” he says.

In what feels like a good sign, large numbers of children are contributing data, through the year and during the tree festivals, some as part of their school’s account on the website, others independently. Among these is Jyothiradithya MA, 18, from Pinarayi in Kerala. He has a sheet dedicated to the dates on which the first mango flowers appear on a tree near his home.

It helps to catch them young, Ramaswami adds. “Then perhaps their relationship with nature will be less exploitative and extractive, and more one of preservation and wonder.”